Multiple matrix magnetic separation device and method

ABSTRACT

A MULTIPLEX MATRIX MAGNETIC SEPARATION DEVICE AND METHOD INCLUDING ELECTROMAGNETIC COIL MEANS FOR PROVIDING A MAGNETIC FIELD VOLUME IN THE SPACE ENCOMPASSED BY THE ELECTROMAGNETIC COIL MEANS, A PLURALITY OF MAGNETIC MATRICES STACKED WITHIN THE SPACE ENCOMPASSED BY THE ELECTROMAGNETIC COIL MEANS, A PLURALITY OF FLOW CONTROL MEANS DISPOSED BETWEEN THE MAGNETIC MATRICES AND ONE ON EACH END OF THE STACK OF THE MAGNETIC MATRICES, EACH OF THE FLOW CONTROL MEANS DISPOSED BETWEEN THE MAGNETIC MATRICES INCLUDING A DISTRIBUTION NETWORK FOR DISTRIBUTING THE SLURRY WHICH UNDERGOES MAGNETIC SEPARATION TO THE CORRESPONDING ADJACENT MAGNETIC MATRIX AND A COLLECTION NETWORK FOR COLLECTING THE SLURRY FROM THE OTHER CORRWSPONDING ADJACENT MAGNETIC MATRIX AFTE THE SLURRY HAS UNDERGONE SEPARATION, ONE OF THE FLOW CONTROL MEANS AT ONE END OF THE STACK OF MAGNETIC MATRICES INCLUDING ONE OF THE DISTRUBUTION AND COLLECTION NETWORKS AND THE OTHER OF THE FLOW CONTROL MEANS AT THE OTHER END OF THE STACK INCLUDES THE OTHER OF THE NETWORKS, INLET MEANS FOR DELIVERING SLURRY WHICH IS TO UNDERGO SEPARATION TO THE DISTRIBUTION NETWORKS AND OUTLET MEANS FOR RECEIVING FROM THE COLLECTION NETWORKS SLURRY THAT HAS UNDERGON SEPARATION.

Nov. 6, 1973 J. J. NOLAN 3,770,629

MULTIPLE MATRIX MAGNETIC SEPARATION DEVICE AND METHOD Filed June l0,1971 2 Sheets-Sheet l [14 r/12 L0 m 22% 2o) /14 flea 156 fla 'MFQIIWZ](460 0 O 40/ //x/ f NOV. 6, 1973 J, J, NOLAN 3,770,629

MULTIPLE MATRIX MAGNETTC SEPARATION DEVTCE AND METHOD Filed June 10,1971 2 Sheets-Sheet 2 /JHTH 12a United States Patent O 3,770,629MULTIPLE MATRIX MAGNETIC SEPARATION DEVICE AND METHOD John J. Nolan,Randolph, and Peter G. Marston, East Gloucester, Mass., and Laszlo M.Lontai, South Bend, Ind., assignors to Magnetic Engineering Associates,Inc., Cambridge, Mass.

Filed June 10, 1971, Ser. No. 151,765 The portion of the term of thepatent subsequent to Dec. 14, 1988, has been disclaimed Int. Cl. B01d17/06 U.S. Cl. 210-42 20 Claims ABSTRACT OF THE DISCLOSURE A multiplexmatrix magnetic separation device and method including electromagneticcoil means for providing a magnetic iield volume in the spaceencompassed by the electromagnetic coil means, a plurality of magneticmatrices stacked within the space encompassed by the electromagneticcoil means, a plurality of ow control means disposed between themagnetic matrices and one on each end of the stack of the magneticmatrices, each of the ow control means disposed between the magneticmatrices including a distribution network for distributing the slurrywhich undergoes magnetic separation to the corresponding adjacentmagnetic matrix and a collection network for collecting the slurry fromthe other corresponding adjacent magnetic matrix after the slurry hasundergone separation, one of the iiow control means at one end of thestack of magnetic matrices including one of the distribution andcollection networks and the other of the ow control means at the otherend of the stack includes the other of the networks, inlet means fordelivering slurry which is to undergo separation to the distributionnetworks and outlet means for receiving from the collection networksslurry that has undergone separation.

FIELD OF INVENTION This invention relates to a magnetic separationdevice and method for separating materials of differing magneticsusceptibility, and more particularly to such a magnetic separationdevice having multiple magnetic matrices.

SUMMARY OF INVENTION The invention features a multiple matrix magneticseparation device having an electromagnetic coil means for providing amagnetic field volume in the space encompassed by the electromagneticcoil means. There are a plurality of magnetic matrices stacked withinthe space encompassed by the electromagnetic coil. A plurality of flowcontrol means are disposed between the magnetic matrices and one on eachend of the stack of magnetic matrices. Each of these flow control meansdisposed between the magnetic matrices includes a distribution networkfor distributing the slurry to undergo magnetic separation to itscorresponding adjacent magnetic matrix and a collection network forcollecting the slurry from its other corresponding adjacent magneticmatrix after the slurry has undergone separation. The flow control meansat one end of the stack of magnetic matrices includes one of thedistribution and collection networks and the flow control means at theother end of the stack includes the other network. There are inlet meansfor delivering slurry to undergo separation to the distribution networksand outlet means for receiving from the collection networks slurry thathas undergone separation.

DISCLOSURE OF PREFERRED EMBODIMENT Other objects, features andadvantages will occur from the following description of a preferredembodiment and the accompanying drawings, in which:

FIG. l is a cross sectional diagrammatic elevational view taken on adiametric plane through a cylindrical multiple matrix separation deviceaccording to this invention.

FIG. 2 is an elevational diagrammatic view of the device of FIG. 1 withthe ferromagnetic return frame omitted and with portions of parts of thedevice broken away to show the distribution networks and collectionnetworks in the various flow control members and the inlet and outletmeans which supply those networks.

FIG. 3 is a cross sectional plan view of a iiow control member takenalong line 3-3 of FIG. 2 exposing a typical distribution network andcollection network.

FIG. 4 is a view similar to FIG. l depicting a portion of the machine tothe right of the center line showing an alternative embodiment of theinvention.

The invention may be embodied in a multiple matrix magnetic separationdevice including a cylindrically shaped electromagnetic coil withinwhich is disposed a plurality of magnetic matrices with interstitialiiow control members; the matrices are generally arranged in a stack andthere is an additional flow control member at the top of the stack andat the bottom of the stack. Each of the interstitial ow control membersincludes a distribution network for distributing to its correspondingmagnetic matrix the slurry which is to undergo magnetic separation and acollection network for collecting the slurry from its othercorresponding magnetic matrix after the slurry has undergone separation.The flow control member at one end of the stack contains either adistribution network or a collection network and the flow control memberat the other end of the stack contains the other of those networks. Inthe preferred embodiment the ow control members should be offerromagnetic material. If, however, their thickness in the direction ofthe field is small compared to the thickness of the matrices they may beof a low permeability material and still satisfy the requirements ofthis invention. Provision is made for connection of an inlet means tosupply slurry to each of the distribution networks and outlet means toremove the slurry from each of the collection networks. The magneticmatrix generally includes a ferromagnetic material such as steel wool,steel balls, or steel tacks enclosed in a canister which may be made ofa stainless steel or other material of low magnetic permeability. Theelectromagnetic coil, multiple matrices and flow control members may beenclosed in a ferromagnetic return frame to increase the eiiiciency ofthe magnetic circuit. The technique of stacking magnetic matricesadjacent to each other to achieve a predetermined matrix area instead ofusing a single matrix of the same area may be employed to reduce thevolume of the ferromagnetic return frame surrounding the coil. Eachadditional layer used in the stack to accomplish a particular arearequirement reduces the diameters of the top and bottom portions of thereturn frame, the intermediate cylindrical portion and theelectromagnetic coil and increases the length of the coil andcylindrical portion of the frame in the direction of slurry flow. Thenumber of matrices used to accomplish a particular process capacityshould Ibe optimized for maximum efficiency and in some cases it mayeven be determined that a single layer is the optimum configuration. Butin those configurations wherein two or more matrices arranged in a stackprovide greater efficiency than a single large matrix the multiplematrix separation device of this invention becomes a particularly usefuland efficient device.

In alternative configurations, instead of one electromagnetic coilcoextensive with all of the matrices, a number of electromagnetic coilsmay be used. For example, a number of electromagnetic coils equal innumber to the number of matrices may be used. -Each electromagnetic coilis associated with a particular one of the magnetic matrices and the owcontrol members may be extended between and radially beyond the coils toprovide an alternative means for connecting the distribution andcollection networks with inlet and outlet means, respectively.

The electromagnetic coil or coils used in a device are not limited tothe conventional variety: they may be superconducting or even cryogenicelectromagnetic coils. If, for example, superconducting electromagneticcoils are employed, the costs of electric power used to generate thesemagnetic fields is no longer a critical factor and the added efficiencycontributed by the return frame may not be signiticant. The return framemight still be used to achieve better magnetic field distribution,especially for large diameter to height ratio systems. However, if inany particular separation operation the optimum design produces amultiple matrix stacked array that is sufficiently narrow, i.e. is of asmall radius, so that the increase of eliciency and field uniformitycontributed by the return frame is no longer significant, the returnframe may be omitted.

There is shown in FIG. 1 a multiple matrix magnetic separation deviceincluding a ferromagnetic return irame 12 consisting of disc-shaped polepieces or pole sections, upper and lower portions 14 and 16, and acylindrical intermediate portion 18 within which is disposedelectromagnetic coil 20 which is cylindrical in shape. The polesections, upper and lower portions 14 and 16, are ferromagnetic membersof substantial mass located closely adjacent the matrices. Pole portions14 and 16 by their size and positions provide a low reluctance path forthe magnetic field whereby the major portion of the magnetomotive force(MMF) provided by coil 20 is presented by the pole portions 14 and 16across the matrices and MMF drops in the rest of the circuit areminimized. The presence of the pole portions, particularly the partsdirectly above and below the matrices, ser-ve to concentrate the fieldand direct it through the matrices parallel to the direction of slurryflow. Centrally located and encompassed by electromagnetic coil 20 is amultiple matrix array 22 which includes in this specific embodiment foursteel |wool magnetic matrices 24, 26, 28, and 30, each of which iscontained in a stainless steel canister 32, 34, 36, and 3'8,respectively. Between each pair of these matrices are ow control members40, 42, and 44, each of which contains a distribution network and acollection network, not shown in FIG. 1, but depicted in detail in FIG.2. At each end of the array 22 are two more ow control members 46 and48, each of which includes only one network, either a collection networkor a distribution network, not here shown, but which appear in detail inFIG. 2. 'Ihe determination of which type of network each of ow controlmembers 46 and 48 includes depends upon the direction of flow of theslurry through the matrices: if the ow enters the matrices from thelower side and leaves them from the upper side, then ow control member46 contains a distribution network and iow control member 48 contains acollection network. If the slurry passes through in the other direction,the converse is true, as will be apparent from the description of FIG.2. Inlet and outlet means for delivering and receiving slurry to andfrom the distribution and collection networks, respectively, are notshown in FIG. 1, but are shown in FIG. 2. The magnetic eld 50 providedby electromagnetic coil 20 passes generally vertically through array 22in a direction generally parallel to the direction of slurry ow throughthe matrices. 'Ihe ferromagnetic return frame 12 which is useful topromote efficient use of the magnetic field 50 when the diameter of thecoil is large and its length in the direction of the slurry liow issmall, becomes less so as the multiple matrix device of this inventiontends toward a smaller radius configuration: a coil longer in thedirection of slurry flow but smaller in terms of radius. Such areduction inuences the magnetic design such that in some cases thereturn frame, particularly the portion 18, may become of insubstantialvalue.

Flow control member 44, FIG. 2, includes a distribution network 52 thatfeeds slurry to matrix 30. Distribution network 52 includes a pluralityof radial extending passages 54 which extend outward from the center ofthe member like spokes of a Wheel and are fed by a central chamber 56which is supplied by inlet pipe S8. Each of passages 54 includes aplurality of ports 60, each of which communicates with the lower edge ofmatrix 30, through ports 60' in canister 38. Suitable sealing betweenthe canisters and ow members is provided to prevent leakage. Sealing maybe accomplished by cylinders surrounding the matrix and between the flowcontrol members. In any event, suitable sealing is provided in array 22to prevent leakage, but has been omitted here because sealing techniquesare known in the art and their depiction here would not contribute to abetter understanding of the invention. Similarly, flow control member 42includes distribution network 61 having ports 62 disposed on radialpassages 64 fed by annular channel 66 which in turn is supplied withslurry by inlet pipe 68; flow control member 40 includes distributionnetwork 69 having ports 70 in radial passages 72 fed by annular channel74 supplied with slurry by inlet pipe 76. Since the llow of slurrythrough the matrices of array 22 has been assumed as upward from bottomto top, ilow control member 46 includes only a distribution network 78Whose ports in radial passages 82 are fed by annular channel 84 suppliedwith slurry by inlet pipe 86. Inlet pipes 58, 68 and 76 are accommodatedin bore 88 of ow control member 46 and sealing sleeve 90 in matrix 24.lInlet pipes 58 and 68 are accommodated as well by bore 92 in flowcontrol member 40 and sealing sleeve I94 in matrix 26; and piupe 58 isaccommodated by bore 916 in flow control member 42 and sealing sleeve 98in matrix 28. Ports l62, 70 and 80 in ow control members correspond withports 62', 70 and 80 in canisters 36, 34, and 32, respectively.

IEach of flow control members 40, 42 and 44 also includes a collectionnetwork 100, 102, 104 having ports 106, 108, connected to radialpassages 112, 114, 116 which discharge into annular channels 118, 120,122 which expel the slurry through outlet pipes 124, 126, 128, allrespectively. Since the direction of slurry flow through the array 22 isupward from bottom to top, ow control member 48 also includes acollection network having ports 132 connected with radial passages 134which discharge into annular chamber 136 that removes the slurry throughoutlet pipe 138. Ports 106, l108, 110 and 132 in ilow control members40, 42, 44 and 48 correspond with ports 106', 108', 110 and 132 incanisters 32, 34, 36 and 38, respectively.

Although in the specific embodiment shown in FIG. 2 the slurry is fedinto the matrices by inlet pipes which enter in the center of the arrayand is removed by outlet pipes which are connected to the periphery ofthe array this is not a limitation of the invention: the positions ofthe inlet and outlet pipes may as Well be reversed, or some of the inletpipes may be at the center and some at the periphery and likewise withthe outlet pipes, or all pipes could be at the center or at theperiphery. Various other delivery removal schemes may be used withoutdeparting from the scope of the invention. Inlet pipes 58, 68, 76, 86are connected in parallel to a source of raw feed and outlet pipes 124,126, 128 and 138 are connected in parallel to an output line or otherreceptacle.

The distribution network 61 and collection network 102 in flow controlmember 42 is shown more completely in FIG. 3. Distribution network 61includes eight passages 64, each of which contains six ports 62 thatfeed slurry to magnetic matrix 28. Each of passages 64 extends radiallyoutwardly from annular channel 66 which is concentric with and locatednear the center of ilow control member 42. Annular channel 66 receivesslurry from inlet pipe 68 disposed in bore 92.

Collection network 102 includes a plurality of passages 114 extendingradially inwardly from annular channel 120 which remove the slurrythrough outlet pipe 126. Each passage 114 includes six ports 108.

The distribution and collection networks shown in FIGS. 2 and 3 are butone configuration for such networks and many other designs andvariations are possible. For example, ports may be added to annularchannels 66 and 120. The channels and passages may be progressivelyreduced in diameter as the distance from the inlet and outlet pipesincreases: the diameter of the channel 66 and passages 64 may be reducedas the distance from the inlet pipe 68 increases. Similarly, thepassages 64 and channel 66 may equally as well operate as a collectionnetwork and the passages 114 and channel 120 operate as the distributionnetwork. In addition, the generally radial design pictured in FIG. 3 isnot a necessity to either the distribution or collection networks as anysuitable rectilinear, curvilinear, or combinations of paths and shapesmay be used.

The magnetic field 50', FIG. 4, need not be supplied by one singleelectromagnetic coil, as shown in the embodiment of FIG. 1, but rathermay be supplied by a plurality of electromagnetic coils 150, 152, 154,and 156, stacked in the same manner as the matrices 24, 26, 28 and 30.In such an arrangement, the ve control members 40, 42, 44, 46, and 48may be extended between and beyond coils 150, 152, 154, and 156 anddirectly connected to pipes 158, 160, 162, 164, and 166 which may, forexample, be the inlet pipes, and a second set of similar pipes, notshown, may serve as the outlet pipes.

Other embodiments will occur to those skilled in the art and are withinthe following claims:

What is claimed is:

1. A multiple matrix magnetic separation devlce comprising:

a plurality of separate magnetic matrices in a stacked array, theboundaries between said separate magnetic matrices in said stacked arraybeing transverse to the direction of ow through said matrices of slurryto undergo magnetic separation;

electromagnetic coil means surrounding said stacked array of matricesfor providing a magnetic eld volume in the space occupied by saidstacked array of matrices;

a plurality of flow passage means disposed between the magnetic matricesand one on each end of the stack of said magnetic matrices; each of saidflow passage means disposed between said magnetic matrices including adistribution network for distributing the slurry to undergo magneticseparation to its corresponding said magnetic matrix and a collectionnetwork for collecting the slurry from its other magnetic matrix afterthe slurry has undergone separation, one of said flow passage means atone end of the stack of said magnetic matrices including a one of saiddistribution and collection networks and said ow passage means at theother end of the stack including the other of said networks; and

inlet means for delivering slurry to undergo separation to saiddistribution networks and outlet means for receiving from saidcollection networks slurry that has undergone separation.

2. The device of claim 1 in which said electromagnetic coil meansincludes a plurality of coils one associated with each of said matrices.

3. The device of claim 2 in which said ow control means extend beyondthe inner periphery of said coils.

4. The device of claim 2 in which said ow control means extend beyondthe outer periphery of said coils.

5. The device of claim 1 in which said ilow control means extendgenerally to the inner periphery of said electromagnetic coil means. y

6. The device of claim 1 in which said ow control means includeferromagnetic material.

7. The device of claim 1 in which each of said networks includes aplurality of ports communicating with its associated said magneticmatrix and conduit means for connecting said ports to the appropriateone of said inlet and outlet means.

8. The device of claim 1 in which said electromagnetic coil means isannular and said matrices present a circular area to the slurry flow.

9. The device of claim 1 further including a ferromagnetic return frameproximate said electromagnetic coil means including a rst portionadjacent one side of said coil means and extending over said spaceencompassed by said electromagnetic coil means and a second portionadjacent the other side of said electromagnetic coil means and extendingover said space.

10. The device of claim 9 in which said return frame further includes athird portion extending about the external periphery of saidelectromagnetic coil means between said rst and second portions.

11. A method of separating material of different magnetic susceptibilitycomprising: supplying slurry to undergo separation to inlet means,directing the slurry to a plurality of distribution networks in aplurality of flow passage means; distributing the slurry from each ofsaid distribution networks into a respective associated one of aplurality of separate magnetic matrices in a stacked array theboundaries between said matrices in said stacked array being transverseto the direction of flow through said matrices of said slurry; providingfrom electromagnetic coil means surrounding said stacked magneticmatrices, a magnetic field in said stacked matrices; collecting theslurry that has undergone separation from each of said matrices in arespective associated one of a plurality of collection networks in saidow passage means; and introducing the slurry that has undergoneseparation from said collection networks into outlet means for removingsaid slurry that has undergone separation.

12. The method of claim 11 in which said electromagnetic coil meansincludes a plurality of coils one associated with each of said matrices.

13. The method of claim 12 in which said flow control means extendbeyond the inner periphery of said coils.

14. The method 0f claim 12 in which said ilow control means extendbeyond the outer periphery of said coils.

15. The method of claim 11 in which said flow control means extendgenerally to the inner periphery of said electromagnetic coil means.

16. The method of claim 11 in which said flow control means includeferromagnetic material.

17. The method of claim 11 in which each of said networks includes aplurality of ports communicating with its associated said magneticmatrix and conduit means for connecting said ports to the appropriateone of said inlet and outlet means.

18. The method of claim 11 in which said electromagnetic coil means isannular and said matrices present a circular area to the slurry flow.

19. The method of claim 11 further including a ferromagnetic returnframe proximate said electromagnetic coil means including a firstportion adjacent one side of said coil means and extending over saidspace encompassed by said electromagnetic coil means and a secondportion adjacent the other side of said electromagnetic coil means andextending over said space.

7 8 20. The method of claim 19 in which said return frame 3,633,751 1/1972 Stevens 210222 further includes a third portion extending about theex- 3,627,678 12/ 1971 Marston 210--222 ternal periphery of saidelectromagnetic coil means be- 3,581,898 6/ 1971 Tyrrell 210-222 tweensaid rst and second portions. FOREIGN PATENTS References Cited 5 801,0039/ 1958 Great Britain 210-223 UNITED STATES PATENTS FRANK A. SPEAR, JR.,Primary Examiner r T. A. GRANGER, Assistant Examiner 2,149,764 3/1939Frei 210*223 10 U S C1 X R 2,329,893 9/1943 Girard 210-222 2,317,7744/1943 Kick et al. 210-222 209-232; 21o-222 3,567,026 3/1971 Holm210--222

